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MA1006/decls.tex

@@ -22,9 +22,16 @@
 \newcommand{\polar}[2]{#1\paren{\cos{\paren{#2}} + i\sin{\paren{#2}}}}
 \newcommand{\adj}[1]{\operatorname{adj}#1}
 \newcommand{\card}[1]{\left|#1\right|}
+\newcommand{\littletaller}{\mathchoice{\vphantom{\big|}}{}{}{}}
+\newcommand{\restr}[2]{{% we make the whole thing an ordinary symbol
+  \left.\kern-\nulldelimiterspace % automatically resize the bar with \right
+  #1 % the function
+  \littletaller % pretend it's a little taller at normal size
+  \right|_{#2} % this is the delimiter
+  }}
 
 \makeatletter
-\renewcommand*\env@matrix[1][*\c@MaxMatrixCols c]{%
+\renewcommand*{\env@matrix}[1][*\c@MaxMatrixCols c]{%
   \hskip -\arraycolsep
   \let\@ifnextchar\new@ifnextchar
   \array{#1}}